At the London Speciality and Fine Food Fair that ended on September 7, functional drinks were introduced including the RDA Organics line that boasts a variety of fruit flavors with "Immune Booster" and "Packed with Antioxidants."

However the US Food and Drug Administration has warned both Canada Dry and Lipton that their products' packed with antioxidants are misleading, promising unsubstantiated health claims.

In the case of Canada Dry's Sparkling Green Tea Ginger Ale the FDA wrote in an August 30 warning letter that it "does not consider it appropriate to fortify snack foods such as carbonated beverages" and the use of the term "enhanced" misleads consumers about its content of antioxidants "derived from green tea or green tea flavonoids."

The same was written in an August 23 warning letter addressing Lipton Green Tea 100% Natural Naturally Decaffeinated and its websites. The FDA also noted, "therapeutic claims on [Liptont.com] establish that the product is a drug because it is intended for use in the cure, mitigation, treatment, or prevention of disease. Your Lipton Green Tea 100% Natural Naturally Decaffeinated product is not generally recognized as safe and effective for the above referenced uses and, therefore, the product is a 'new drug'."

These teas are not the only ones to find themselves in hot water.

Kombucha tea was pulled off Whole Foods shelves in June for its natural alcohol content that require it to belong in an alcoholic beverage category regardless of its probiotic benefits.

And, Coca-Cola defended its Vitaminwater in court against FDA claims that it isn't healthy in August despite having 33g of sugar in each bottle with the promotional jargon claiming if you drink a bottle you will be "healthy as a horse" and in a "healthy state of physical and mental well-being."

The blog HuffingtonPost noted Coca-Cola's defense: "no consumer could reasonably be misled into thinking Vitamin Water was a healthy beverage."